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How to prevent iPhone audio interference in speakers iOS devices
Ever since I started listening to music in my car from my iPhone, I've been dealing with the annoying electromagnetic interference problem (loud buzz / static / popping / digital noise coming through car speakers). I set out to find a solution today, and to make a long story short, here's what I settled on: taping two small pieces of aluminum foil on the back of the iPhone in a specific location, as seen in this picture. Here's what I did:
  1. Cut out a 2" x 3" piece of aluminum foil.
  2. Fold foil in half horizontally (foil is now 2" x 1.5").
  3. Tape foil from the bottom right corner (on the back of the iPhone) up to the middle of the text iPhone (Picture #1, Picture #2) using electrical tape.
That's it; no more buzz/static/popping sounds coming out of your speakers!

Another solution which avoids using tape (although electrical tape leaves no residue whatsoever on the iPhone) is simply placing the iphone on a sheet of aluminum foil. This might be a better idea for people experiencing this problem in a static environment rather than a car (i.e. iPhone on office desk with nearby computer speakers). After discovering this solution, I also saw another potential solution online, using aluminum foil wrapped around the audio cable coming out of the phone. I haven't tested that method, but it looks much more obtrusive.

For me, other materials didn't work (at least not perfectly). I also tried various sizes of aluminum foil in various locations -- you could probably get by with a smaller amount of foil, but this amount works 100% (so far at least). I guess it should also be noted this solution could potentially work for other GSM phones with this issue (i.e. Blackberries, Sidekicks) -- you'll just have to experiment with the size of the foil and its location.
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How to prevent iPhone audio interference in speakers
Authored by: haralds on Jan 07, '08 07:56:14AM

What you are doing is shielding the GSM antenna, which will prevent the cell phone from receiving or sending calls, or at least significantly reduce the signal strength. Since the phone has a harder time connecting to the cell tower, it will also boost its signal strength, reducing battery life.

You might be better off putting it in airplane mode, or placing it in a location, where it interferes less with the audio signals.



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How to prevent iPhone audio interference in speakers
Authored by: bcometa on Jan 07, '08 09:45:11AM

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What you are doing is shielding the GSM antenna, which will prevent the cell phone from receiving or sending calls, or at least significantly reduce the signal strength. Since the phone has a harder time connecting to the cell tower, it will also boost its signal strength, reducing battery life.
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That's what I thought, but did you actually try it? While what you said sounds correct and makes sense, the signal strength appears to be exactly the same. Adding/removing the foil seems to have no effect on the wireless "bars" or reception (making/receiving phone calls/email/text messages) as far as I can tell. Perhaps battery life is being shortened, but I've still never had to recharge my iPhone more than once a night since first getting it, so at least for me it's not a noticeable difference.

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You might be better off putting it in airplane mode, or placing it in a location, where it interferes less with the audio signals.
-

While airplane mode also solves the problem, one can not make/receive text/email/phone calls/web surf, the main reasons for having an iPhone.

I should also note that since submitting the original hint, I've decided to remove the tape/foil from the back of the phone (for cosmetic purposes). Now, I have lined my car phone holder (the kind that holds onto your air conditioner vents) with aluminum foil and electrical tape. Since I only have this problem in my car, and since I always have my iPhone in my car phone holder when in my car, this solution makes more sense for me - iPhone still looks great, speaker interference problem in car is gone, and reception, if in any way compromised (as haralds suggested), is contained to the car.



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How to prevent iPhone audio interference in speakers
Authored by: xfrosch on Jan 07, '08 03:17:56PM

You shouldn't be taking calls or surfing while you drive anyway. I have to share the damn road with your distracted ass.

For an arbitrary modification of an antenna pattern, it's impossible to tell what the effect in a given direction will be without detailed testing. Your transmission/reception will be worse in most directions, but might actually be better in others. The problem is that if you succeed in reducing emissions in the direction of your stereo, you will also reduce the efficiency of your phone in that direction, and at least part of the time that will be the direction in which the base station lies.

You might interfere with the pattern so much that your phone actually acquires ANOTHER, farther away, base station rather than the one whose cell you are in. Theoretically you could jump from one cell to another merely by pointing your car (and thus your phone) in a different direction.

If you were to succeed in blocking energy transmission (and thus stereo interference) in ALL directions, you would also block incoming signals from all directions. That's called the "principle of reciprocity", and it's the first thing they teach you in a course in antenna engineering.

Worse yet, the energy your phone was trying to radiate would still have to go SOMEWHERE. It would reflect back into your phone, which can't be a good thing; it's pretty closely analogous to putting a sheet of aluminum foil into your microwave, or running the microwave with nothing in it.

How often are calls dropped or phones damaged in practice? I don't know. That's the kind of thing that radio engineers might write master's theses or doctoral dissertations on, if they were really starved for inspiration.



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How to prevent iPhone audio interference in speakers
Authored by: frgough on Jan 07, '08 03:24:22PM

When you stop listening to the radio, talking to a passenger or looking at a cute girl while driving, you can give us lectures on distracted cell phone users.

Until then, spare us the example of how you've been brainwashed by the same control freaks that think it's cool to ban the incandescent light bulb.



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How to prevent iPhone audio interference in speakers
Authored by: hjeff on Feb 05, '09 02:01:01AM

If it's of interest, there have many studies going over these effects on real drivers showing that cell phone use (handheld or not) has a much more serious detrimental effect on driving than talking to a passenger, listening to the raido, looking at a cute girl, or even eating. It's right up there with drinking and sleepiness.

As someone who walks and rides his bike a lot, I can tell you that almost all the close calls caused by drivers are by those talking on the phone.



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How to prevent iPhone audio interference in speakers
Authored by: lokon1979 on Jan 08, '08 08:03:47AM

keeping your cell phone turned on while driving doesn't mean you have to answer the call. i don't drive, but i always keep the phone on while watching movie or concert, but set it in silent mode. many people don't like to leave voice message, so keep the cell phone on to record missed calls can be a better idea to turn the phone off.



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How to prevent iPhone audio interference in speakers
Authored by: captain caveman on Jan 08, '08 02:31:06PM

>You shouldn't be taking calls or surfing while you drive anyway. I have to share the damn road with your distracted ass.

You should see the training we have to go through to get a pilot's license. You get trained up real good on when it is safe to use a comm device.



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How to prevent iPhone audio interference in speakers
Authored by: brett_x on Jan 07, '08 08:22:51AM

Important note:
Be sure not to use the aluminum foil from your hat to do this. You will undoubtedly leave yourself open to alien/government mind-reading/controlling capabilities.
:/



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How to prevent iPhone audio interference in speakers
Authored by: surrealx on Jan 07, '08 09:31:07AM

This definitely has to do with the radio in the phone. My AT&T 8525 does this as well. Nextel phones are the worst offenders.

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Is there another word for synonym? - George Carlin



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How to prevent iPhone audio interference in speakers
Authored by: osxpounder on Jan 07, '08 10:29:55AM

I hear my cell phone making digital beeps and ripping sounds often through just about any audio device it's near. If I'm recording audio, I must turn the cell phone completely off, or that sound will get into the recording. Powered speakers, attached to my old bedroom Mac, pick up the sound even when the Mac is shut down. If I forget to turn off the powered speakers, I will be awakened by that loud set of beeps and ripping digital glitch sounds. It lasts about 1.5 seconds, and seems to do it once or twice an hour.

I hear it on my car radio, I hear it out of my computer speakers... everywhere there are speakers. Lots of phones seem to do this. It's very annoying; I thought this is the sort of thing that FCC regulations were supposed to prevent, but the removal of such regulation means I have to put up with this crapola.

I use a Cingular Go-Phone, some kind of Motorola that has no indication of a model name whatsoever, but I don't think it matters what kind of phone it is much. Mine wouldn't be a GSM, I don't think, but I don't know or care much about cell phone tech.



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How to prevent iPhone audio interference in speakers
Authored by: westont on Jan 07, '08 12:45:37PM

This hint highlights an aspect of GSM-based cell-phones that is experienced by thousand of users each day. While the steps taken here may have alleviated the problem, they may also (as a previous post indicated) have reduced the effectiveness of the receiver in the phone.

There is almost certainly nothing wrong per-se with the phone or the car audio system. It is just an unfortunate fact that the type of bursty modulation used in GSM phones (Time Division Multiplexed GMSK/8PSK) results in an amplitude modulated component in the audible range (around 200Hz) which then has a propensity to be demodulated and amplified by susceptible audio equipment.

You may also find that experimenting with the location of the phone relative to the car audio system may help considerably, Naturally though, your mileage may vary as it may not be possible to eliminate the problem entirely by doing so.

Unless specific steps have been taken with the circuit design, most audio equipment will exhibit the problem to a greater or lesser degree - the quality of the shielding and the design just dictates how physically close the phone has to be before the problem is heard.

Interestingly, this is an inherent design problem for the audio circuitry of the GSM phone that needs careful attention to ensure adequate interference rejection with minimal impairment to voice quality!



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How to prevent iPhone audio interference in speakers
Authored by: dfbills on Jan 07, '08 01:22:50PM
This seems like a really bad idea. I'd be curious to see how much signal strength you loose with this compromise.

Apple <a href="http://dfbills.com/display/357">recommends</a>not even holding your hand over this area when using the phone. Putting metal over it is most likely a "bad thing."

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-d

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How to prevent iPhone audio interference in speakers
Authored by: bcometa on Jan 07, '08 06:17:26PM

None (at least according to the signal strength bars).



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How to prevent iPhone audio interference in speakers
Authored by: virusdoc on Jan 07, '08 04:44:38PM

My classic 30gig iPod does this as well, but only on two stereo systems--my car (connected via headphone jack to AUX IN) and a bookshelf radio with and integrated dock. In both situations, touching the click wheel lightly so that the screen backlight comes on solves the problem--at least until the backlight goes off. In my car only, touching the metal housing on the back of the iPod also corrects the problem. I don't think this is a classic ground loop problem with my car stereo since the internal backlight being on corrects the problem.

I mention this only to suggest that this problem might not be unique to the GSM radio, and may instead reflect an unfortunate feedback between the iPod/iPhone audio amp circuitry and certain external amplifiers.



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How to prevent iPhone audio interference in speakers
Authored by: bcometa on Jan 07, '08 06:20:48PM

That sounds more like a problem specific to your ipod. Have you tried a different ipod in your car or dock?



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How to prevent iPhone audio interference in speakers
Authored by: virusdoc on Jan 08, '08 06:20:11AM

Yes. Both my 2nd and 3rd gen nanos play normally in both. So it is possible my Classic has a defect, or that all Classics share this defect. I don't have another Classic to compare to.



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How to prevent iPhone audio interference in speakers
Authored by: 50leaves on Jan 07, '08 06:54:41PM
I was skeptical at first like many of you and tried it myself. I was at work and had 0 problems.

I posted it on my site http://www.50leaves.com/apple/apple-hardware/how-to-stop-iphone-interferance-in-speakers/
because I loved it. Users on my site where also skeptical (which I understand), so I decided to do some heavy test shown in the link above.

It works if you follow the directions. There was no difference is signal strength that I could find.

Hope this helps.

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What does "accept interference" mean?
Authored by: gabester on Jan 07, '08 08:50:46PM

What is the point of FCC regulation and UL certification if devices are going to pump out signals that interfere with the operation of other devices? I have noticed this phenomenon as well with certain phones... even while driving in my car I've been had interference presumably coming from vehicles on the road play through my stereo while playing CDs!

It's quite annoying, but then maybe I am under the misconception that this is NOT supposed to be happening... at least, that's my interpretation of what the "devices must not interfere with and must accept interference from other devices" phrase that always accompanies any FCC licensed wireless device means.
g=



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What does "accept interference" mean?
Authored by: 50leaves on Jan 07, '08 10:04:43PM

I agree, hopefully the next iphone will have this fixed.



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What does "accept interference" mean?
Authored by: ashevin on Jan 08, '08 04:46:36AM

The fault really lies with the speakers. The phone wouldn't work at all as a phone if it couldn't broadcast. The speakers should be properly shielded to only accept signals from the incoming cabling if they don't want interference from nearby electrical sources. Keep in mind that any electrical source outside the speakers may interfer with them.

Also, the FCC wording only means that the devices should not interfer with proper operation. Both the phone and the speakers are still operating properly even if one is affecting the other.



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What does "accept interference" mean?
Authored by: macevangelist on Jan 08, '08 05:50:28AM

Devices must not interfere in the sense of limiting each other's ability to communicate wirelessly. A baby phone must not interfere with a FM radio just like a cordless phone must not interfere with wireless headphones.

There's no wireless technology in loudspeakers so there is nothing that can be interfered with in the first place.



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How to prevent iPhone audio interference in speakers
Authored by: Numbski on Jan 08, '08 08:43:53AM

The problem isn't the phone. The problem is that you don't have properly shielded speakers and speaker wire. My old desktop speakers used to be beautifully shielded (altec-lansing, about 10 years old and still kicking!), but any newer ones use cheaper, unshielded speakers and cable.

While the speakers are hard to fix, the wires aren't. Simply wrap your speaker wires in aluminum foil, find a ground in the speaker system, and solder a wire to that ground and to the foil. I've been looking for the equivalent of a cable "jacked" that's sheilded to put around my computer speaker cables, but no luck so far. :(



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How to prevent iPhone audio interference in speakers
Authored by: desquared on Jan 11, '08 08:59:37PM

Thanks for the hint. I couldn't stand that GSM noise!!!

I found a small issue where my phone had "no service" in an urban area I always get reception. This was right after I had applied the foil and went on a ride in the car. I think I was switching towers but it passed in about 3 minutes and it was back up to "full bars." Could have been a ton of other things, but the foil on the phone was the most obvious variable.

This hint doesn't effect BT transmissions for me.

Also, to avoid taping an unsightly piece of tinfoil on the phone, I mounted the tinfoil in the GI plastic iPhone case from Cingular.

THANKS AGAIN FOR A HUGE HINT!

I'm curious if this will lessen the effect at my office desk as the last time I had my phone near my desk computer the speaker freaked out... 'til Monday



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great hint, got me thinking...
Authored by: spacericker9k on Apr 01, '08 02:09:52PM

since my problem is only at home with my stereo, all i did was place a couple of pieces of aluminum foil near my speakers and it worked perfectly. no more interference

oh relief!!!! that noise drove me insane



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